It is easy to think of the computing cloud as the placeless whereabouts of the latest Netflix series, your Spotify playlists, millions of wanton selfies and your digital assistant. It is even easier to ignore it altogether, at least until Alexa alerts you that your storage space is filling up and helpfully offers to rent you extra room, of which there always appears to be more available. Necessary, disembodied and, for $9.99 a month, to all…